Resolving dependencies...
cabal: Could not resolve dependencies:
next goal: yesod (user goal)
rejecting: yesod-1.4.3.1, yesod-1.4.3, yesod-1.4.2.1, yesod-1.4.2,
yesod-1.4.1.5, yesod-1.4.1.4, yesod-1.4.1.3, yesod-1.4.1.2, yesod-1.4.1.1,
yesod-1.4.1, yesod-1.4.0, yesod-1.2.6.1, yesod-1.2.6, yesod-1.2.5.3,
yesod-1.2.5.2, yesod-1.2.5.1, yesod-1.2.5, yesod-1.2.4, yesod-1.2.3,
yesod-1.2.2.1, yesod-1.2.2, yesod-1.2.1.1, yesod-1.2.1, yesod-1.2.0.1,
yesod-1.2.0, yesod-1.1.9.4, yesod-1.1.9.3, yesod-1.1.9.2, yesod-1.1.9.1,
yesod-1.1.9, yesod-1.1.8.2, yesod-1.1.8.1, yesod-1.1.8, yesod-1.1.7.2,
yesod-1.1.7.1, yesod-1.1.7, yesod-1.1.6, yesod-1.1.5, yesod-1.1.4.1,
yesod-1.1.4, yesod-1.1.3.1, yesod-1.1.3, yesod-1.1.2, yesod-1.1.1.2,
yesod-1.1.1, yesod-1.1.0.3, yesod-1.1.0.2, yesod-1.1.0.1, yesod-1.1.0,
yesod-1.0.1.6, yesod-1.0.1.5, yesod-1.0.1.4, yesod-1.0.1.3, yesod-1.0.1.2,
yesod-1.0.1.1, yesod-1.0.1, yesod-1.0.0.2, yesod-1.0.0.1, yesod-1.0.0,
yesod-0.10.2, yesod-0.10.1.4, yesod-0.10.1.3, yesod-0.10.1.2, yesod-0.10.1.1,
yesod-0.10.1, yesod-0.9.4.1, yesod-0.9.4, yesod-0.9.3.4, yesod-0.9.3.3,
yesod-0.9.3.2, yesod-0.9.3.1, yesod-0.9.3, yesod-0.9.2.2, yesod-0.9.2.1,
yesod-0.9.2, yesod-0.9.1.1, yesod-0.9.1, yesod-0.8.2.1, yesod-0.8.2,
yesod-0.8.1 (constraint from user target requires ==0.8.0)
trying: yesod-0.8.0
trying: direct-plugins-1.1 (dependency of yesod-0.8.0)
next goal: ghc (dependency of direct-plugins-1.1)
rejecting: ghc-8.0.1.20161018/installed-8.0... (conflict: ghc =>
bytestring==0.10.8.1/installed-0.1..., yesod => bytestring>=0.9 && <0.10)
Dependency tree exhaustively searched.